Guam - Away - 2011
I'm currently struggling to find photos of this shirt in use. However, I have found a video from the AFC U19 Championships. It was worn during Guam's 26-0 defeat to Japan in October:
The shirt was sold to me as "match worn U19 shirt" by a Thai seller. Since the AFC U19 Championships was hosted by Thailand, then I am inclined to believe them.